Added sub-step to "Getting Started with Docker"

Added a sub-step to #4 "Getting Started with Docker" to add your career account to 'docker-users' if you receive an error about docker permissions/privileges.

README.md

@@ -5,7 +5,7 @@ Files & notes for a series of docker tutorials for coworkers.
 ## 1. Getting Started with Docker
 
 1. Install [Docker Desktop](https://www.docker.com/products/docker-desktop/)
-2. Open a terminal. Some options:
+3. Open a terminal. Some options:
   * Windows: Lots of options
     * Use the Docker Desktop terminal
     * Or use the Windows Subsystem for Linux (WSL) with Ubuntu or another distro
@@ -15,7 +15,9 @@ Files & notes for a series of docker tutorials for coworkers.
     * Or PowerShell
   * Mac: Use the Terminal app
   * Linux: I think you know already. By the way, is anyone using desktop Linux?
-3. Run `docker run hello-world` to make sure Docker is installed and working.
+4. Run `docker run hello-world` to make sure Docker is installed and working.
+    * You may need to first add your career/user account to the group 'docker-users' in Local Users/Groups in Computer Management if you receive the error
+      'docker client must be run with elevated privileges'  (after adding you will need to apply and log out/in to apply the change)
 
 ## 2. Running Python inside Docker